Officials from the Philippine Institute of Volcanology and Seismology (Phivolcs) have yet to determine the height of the lava fountain.

During the event, jets of lava were sprayed into the air by the rapid formation and expansion of gas bubbles in the molten rock, according to scientists.

Lava fountains range from about 10 meters to 100 meters in height, and sometimes reach more than 500 meters, the United States Geological Survey (USGS) said.

Photo courtesy of Joshua Eric Velasco Dandal

The Mayon Volcano alert level was raised to Level 4 on Monday morning, one notch below the highest warning.

This indicates a hazardous eruption is "imminent" and that the danger zone has been extended to an 8 kilometers radius.

Mayon rises 2,460 meters (8,070 feet) above a largely agricultural region some 330 kilometers southwest of Manila. It is considered the nation's most active volcano.

Steam-driven eruptions and rockfalls began earlier this month, and the crater began glowing soon after, in what Phivolcs said was a sign of the growth of a new lava dome. - with reports from Karren Canon, ABS-CBN News; Agence France-Presse